Cushioning device



July 23, 1940. A. F. DICKER, SR 0 ,7

cusmonme DEVICE Filed. March 28, 1939 HIS ATTORNEY Patented July 23, 1940 UNITED STATES C'U SHIONIN G DEVICE Arthur F. Dicker, Sr., Phillipsburg, N. J., assignor to Ingersoll-Rand Company, Jersey City, N. 1., a corporation of New Jersey Application March 28, 1939, Serial No. 264,570 3 Claims. (01. 255-45) This invention relates to rock drilling mechanism, and more particularly to a cushioning device for rock drilling mechanism of the type that is actuated mechanically to and from .the work.

In a more specific sense, the invention is in tended for use in connection with rock drills equipped with a motor for effecting feeding movement. In the operation of apparatus of this charactenonly a comparatively small portion of the operators time is required for manipulating the feeding mechanism. Normally, it is merely necessary to set the feeding motor in operation at the beginning of a cut and to again reverse the motor at the end of the run for retracting the rock drill to its initial starting position. In the interim the operator is freeto perform such other duties as may arise in connection with the work.

Under these circumstances it may happen that the operator is occupied with other matters at the time the rock drill reaches its rearmost position and that the motor is, therefore, not cut off from the power supply before the rock drill engages relatively fixed portions of the drilling mechanism. In such case the rock drill is often forced into such tight locking engagement with other portions of the drilling organization that it is impossible to again start the motor without practically disassembling it to free the rotary elements of the feeding mechanism.

It is accordingly an object of the invention to prevent the feeding motor from forcing the rock drill into tight binding engagement with other portions of the drilling mechanism.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts,

Figure 1 is a longitudinal side elevation of a drilling mechanism equipped with a cushioning device constructed in accordance with the pracand designated by 20, comprises a rock drill 2l,,

a support member or shell 22 and a rotary feeding motor 23 attached to the end of the shell by means of rods 24 for actuating the rock drill 2| longitudinally of the shell.

The rock drill 2| may be provided with the usu l rotary elements of the motor.

hammer piston (not shown) for actuating a drill steel 25 into the work, and on the sides of the rock drill are the usual ribs 26 which extend into guideways 21 in the shell for connectingthe rock drill and the shell slidably together;

Near the rearward end of the rock drill is a depending lug 23 having a bore 29 to receive a feed nut 30 clamped in position by a nut 3| threaded on a rearwardly projecting end of the feed nut and seating against the adjacent end of the lug 28. The feed nut 30 is threaded to accommodate a feed screw 32 which may be suitably supported at its front end by the shell 22 and is in interlocking engagement at its rearward end with the motor 23 whereby the feed screw is rotated.

The motor 23 may be of any suitable pressure fluid actuated type and on its rotor is a gear 33 which meshes with planet pinions 34 mounted upon a spider 35 in the end of the motor casing 36. The spider 35 carries a skirt 3'! which is rotatable in the end of the casing 36 and has a tapered bore 38 to receive a correspondingly tapered shank 39 of the feed screw 32. The shank 39 is locked to the skirt 3! by a key 40, and on the end of the shank is a threaded extension 4| to accommodate a nut 42 that seats upon a shoulder 43 on the spider 35 for securing the spider to the shank 39. Preferably, a bushing 44 is disposed in the end of the casing 36 to provide a renewable bearing surface for the sleeve 31 and on the'outer end of the bushing 44 is a flange 45 which overlies the end of the-casing 36.

The feed screw 32 is of the conventional type having a collar 46 which abuts a thrust plate 41 encircling the shank 39 and seating against the flange 45. Thus, the collar 46 serves to prevent the imposition of severe end thrust upon the feed screw 32 comes sufficiently close to the collar 46 to make it possible for the feed nut to be brought into engagement with the collar. In prior structures of this character this arrangement often brought about a situation in which The thread of the abutment member 48 consisting of two half sections 49 which are disposed slidably about the reed screw to seat against the rearmost end of its thread, and on the opposite end of the member 48 is a reduced stem 50 to receive a ring for retaining the sections 49 on the feed screw.

The ring 5|, in turn, has a stem 52 of reduced diameter to receive an end of a spring 53 which abuts against a shoulder 54 on the ring. The

other end of the spring encircles the collar 46 e and seats against the plate 41. The spring is thus held against vibratory movement laterally of the feed screw and, in practice, is also placed initially under compression so that it will constantly tend to press the member 48 against the end of the thread of the feed screw.

During the operation of the drilling mechanism and when the rock drill approaches its rearmost limiting position the feed nut will engage the member 48. Continued rearward movement of the rock drill will cause the spring 53 to be compressed and, in the event that the operator fails to cut-off the powersupply to the motor, will cause the motor to stall. The rock drill, however, will abut only the member 48 which, although arranged on the feed screw, cannot effect a locking engagement between the rock drill and the feed screw and the rock drill is, therefore, free at all times to proceed in a forwardly direction.

I claim:

1. In a cushioning device for a rock drilling mechanism, the combination of a rock drill and a feed screw in threaded engagement therewith,

a motor for rotating the feed screw, a spring on the feed screw to receive the thrust of the rock drill and thereby prevent the motor from forcing the rock drill into binding engagement with other portions of the drilling mechanism, and means for preventing vibratory movement of the spring with respect to the feed screw.

2. In a cushioning device for a rock drilling mechanism, the combination of a rock drill and a feed screw in threaded engagement therewith, a motor for rotating the feed screw, an abutment for the rock drill slidable on the feed screw, a spring acting against the abutment to resist rearward movement of the rock drill relatively to the feed screw and thereby prevent the motor from forcing the rock drill into binding engagement with other portions of the drilling mechanism, and means for preventing vibratory movement of the spring with respect to the feed screw.

3. In a cushioning device for a rock drilling mechanism, the combination of a rock drill and a feed screw in threaded engagement therewith, a motor for rotating the feed screw, an abutment for the rock drill slidable on the feed screw adjacent the motor, a spring interposed between the abutment and the motor to resist rearward movement of the rock drill with respect to the feed screw and thereby prevent the motor from forcing the rock drill into binding engagement with other portions of the drilling mechanism, and means for preventing vibratory movement of the spring with respect to the feed screw.

ARTHUR F. DICKER, SR. 

